What does v=0 in function parameters means

Question

Here is a modified code from geeks for geeks.

   #include<iostream>
   using namespace std;

   class Test {
    int value;
   public:
       Test(int v = 0) {value = v;}
    int getValue() {return value;} 
   };

   int main() {
       Test t(20);
       cout<<t.getValue();
       return 0;
   }

What does parameter in function Test(int v=0) means?

Answer 1

That is default value for v parameter, which is the v variable will use that value if there is no value passed